function beta=betfsh(r1,r2,rv1,rv2,gamma)
%  calculate coagulation kernel for shear use fractal kernel. 
%  input - r1,r2 radius  cm 
%          gamma   shear in 1/s
%  output- beta coagulation kernel
%                         11 jy 93

%      -  incorporate LI&Logan results by
%		using     a) beta rectilinear * (r1/r2)^power
global ratrirg

clsh=0.785;		% power for shear
ratio=min(r1./r2,r2./r1);

betsh=1.3*gamma*(ratrirg*(r1+r2)) .^ 3;

beta=betsh .*ratio .^ clsh;
